Production of super-bodied oils



Patented Aug. 19, 1952 PRODUCTION or SUPER-BODIED o Ls James A. Arvin, Homewood, IlL, assignor to The Sherwin-Williams Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Application October 26, 1948, Serial No. 56,664

8 Claims.

This invention relates to homogeneous, gel particle-free oils derived from unsaturated fatty acid polyesters, and to an improved .method for their manufacture at atmospheric pressures. More specifically, the invention relates to the production of such fatty oils characterized by viscosities above 14 minutes, herein called super-bodied oils. It is to be understood that the viscosity value referred to herein is based upon the time required for an air bubble to travel the length of a standard Gardner varnish viscosity: tube under standard temperature conditions (77 degrees F.).

Conventionally, heat-bodied oils having viscosity values above 14 minutes are usually lacking in homogeneity, and almost invariably gel upon age to a solid state. Super-bodied, gel-free, homogeneous oils have heretofore been prepared by heat-bodying fatty oils at reduced pressures to produce viscosities above the 10 to i l minute range. The vacuum method of super-polymerizing fatty oils inherently has the mechanical problems of vacuurn operations, high losses and longer periods of time to produce a specified viscosity. This is especially true when viscosities above the range mentioned as critical are desired.

So far as is. known, there are no unusual difficulties encountered in producing oils of 8 to 10 minutes or less in viscosity from drying oils except that by conventional procedure an unduly long time is required. However, it is usual to find with ordinary bodying procedures, after viscosities of about 14 minutes have been produced, the homogeneous appearance of the viscous oil is lost, gel particles are incipient or actually form, and the oil when poured in a fine stream as from a vial, may reveal a string-like characteristic, an initial stage in the transformation from a sol to a gel phase. Varnish makers know when this condition is first observed that the prompt addition of either fatty acids or rosin to the varnish or oil often saves the cook from gelation or monkeying. Complete gelation at bodying temperatures, after incipient gel formation, occurs with great rapidity. Fast action on the part of the oil cooker is necessary to arrest the change from the sol to the gel phase. Such arresting of polymerization is commonly referred to by varnish makers as a checking operation or a check and has for one primary purpose a rapid reduction in the temperature of the batch. In cases where rosin and/or fatty acids are the checking means, it is well known that these acidic materials possess the additional quality of dispersing the primary gel particles Whichhave begun to form in the varnish or oil.

Another practice oil in the art in checking is to direct a stream of water on the outside of the kettle, as from a hose, after cutting off the source of heat. Occasionally, more adventurous varnish makers will purposely direct water into the batch, a dangerous practice which effectively reduces the temperature through heat transfer to the Water and the consequent formation of steam. In general, this practice is condemned and so far as is known there has been no record of observations of the effect of such a procedure upon oils and varnishes so treated. It is obvious that one would not normally resort to such drastic cooling methods unless the end in mind was to reduce the temperature quickly to inhibit greatly the rate of reaction in the kettle. .To replace a gelling batch of oil or varnish on the fire or to continue or to resume heating at such a critical stage would be contrary to all established practice in the art.

To clarify the concept of viscous oil stability, the following test used by the varnish maker may be helpful. Whenv a varnish or oil-maker is in the process of cooking a batch, small samples are removed periodically from the batch and in some cases are further reduced with solvents to a specified solvent-solids content, the sample placed in a standard glass vial or tube leaving a small free air space in the tube. When cooled to standard temperature conditions (e. g., 77 degrees F.), the observer will clock the time required for the air space in the test tube to travel from the bottom to the top of the tube following its. quick inversion.

Through experience, the varnish maker has learned if the small bubble leavesa tall or a tit in the oil as it progresses from the bottom to the top of the tube, that said oil or varnish will probably be unstable with age. That is, polymerization is likely to proceed even after the oil or varnish has been completed and stored. Polymerization may proceed to a point where the product will no longer pour, and the oil will resemble a jelly. It is common experience that oils bodied at atmospheric pressures or above by conventional means to about 10 to 14 minutes may upon test, evidence: this peculiar tail in the bubble, and possess uncertain shelf life.

One of the objects of the present invention is to provide a new and improved process of producing super-bodied homogeneous oils at atmospheric pressures or above.

Another object is to produce new and improved super-bodied oils. Other objects will appear hereinafter.

The ability to produce super-bodied oils at atmospheric pressures and above in accordance with the present invention has been made possible through the observation that oils polymerized to the point where gel particles are ob servable, and heterogeneity between solid and fluid phases in the oil is initiated, can be held a longer period of time at bodying temperatures, the initial gels formed dispersed, and additional gelation prevented by blowing the latently gelling mass with steam.

The process of the present invention for manufacture of homogeneous, super-viscosity oils consists essentially of bodying a fatty oil to a stage of latent or incipient gelation at atmospheric pressures or above, checking the polymerization rate by blowing the fatty oil with steam, and, after the initial checking, again holding the hot oil at or near bodying temperature while passing steam through the heated oil. The preferred method is to heat-body a semi-drying oil by the methods of my co-pending abandoned application, Serial No. 34,809, filed June 23, 1948, to the point of latent gelation (e. g., about 5 to seconds cure point) at which time the viscosity of the oil is indeterminant due to the presence of latent gel particles, and thereafter check the polymerization and blow the oil with steam.

While it is not essential to the production of superpolymer oils to use the bodying methods given in my co-pending application, Serial No. 34,809, filed June 23, 1948, by doing so considerable advantages accrue. It is often possible to body oils by standard means to the point of incipient gelation as a starting point for the manufacture of super-polymer oils and at the point where this process is initiated, said oils having indeterminant viscosities of about 10 to 14 minutes. Soya bean oils or other oils having iodine values classifying them in the semi-drying range cannot be bodied to the point of gelation by standard practice. With some oils, e. g., semi-drying oils, it is essential that catalytic means be employed to body them to the required initial degree to achieve the higher degree of viscosity of the process herein disclosed.

The practice herein disclosed, to return a gelling batch to the fire or to maintain the temperature of the oil after adding water to the hot batch to form steam, or blowing the hot hatch with steam directly after the first gelation symptoms without removal from the fire, is a unique procedure based on the discovery that steam acts as a dispersant for gels formed and an inhibitor against further localized gelation within a varnish or oil batch.

It is surprising that passage of steam through the batch allows continued heating at bodying temperatures even after gelation has become visibly initiated, and that uniform bodying will thereafter continue for a suflicient time to produce oils having Gardner tube viscosities as high as an hour or more, characterized by freedom from localized" over-polymerization or gel particles and by an unbroken, smooth flow from a spade or paddle. The resultant oils also possess a practical shelf life. It has been specifically found that heating may be continued at nearbodying temperature levels to increase the viscosity of the oil and yet maintain a smooth, homogeneous, gel particle-free product provided the sparge or blowing with steam is continued. By steam treatment after first heat-bodying in a conventional manner, it has been found possible to produce oils with viscosities in excess of 14 minutes. If desired, the initial bodying 4 methods disclosed in the previously mentioned co-pending application may be used.

If the super-bodied oils are made by the process herein described, it is possible to produce oils of one hour, more or less, in viscosity yet having complete homogeneity, freedom from gel particles, and as far as is known, excellent stability upon storage.

In practice, after bodying to incipient gelation at a temperature of 500 degrees F. to 625 degrees F. and checking with steam, the temperature is held within or near the bodying range, and the steam blowing is continued at said temperature until a viscosity greater than 10 to 14 minutes and preferably above 20 minutes has developed, and the oil cooled by additives such as additional oil, rosin or other compatible resin or by natural or accelerated cooling to below bodying temperature to inhibit further polymerization. The point at which the polymerization is to be stopped, i. e., the temperature reduced to below the bodying temperature range, is preferably followed by means of cure point values as these values have been found to give accurate control means. The cure value should not be allowed to go below 5 to 10 seconds as at this point gelation of the oil is imminent.

The cure point is a means of observing the progress of a polymerization reaction. Measurement is made by exposing a drop of the reactant to the polished surface of a metal slab maintained at a constant temperature of 200 degrees C. (392 degrees F.) Immediately upon exposure of the drop to the surface, it is spread out over the largest possible area with a pointed metal tool. At the moment of application of the drop to the plate, a timer is started. The film is continuously spread until gelation occurs, and the time required to allow gelation of the film noted. The elapsed time, from application of the drop to the cure plate until gelation of the film is the cure. The smaller the cure value, the nearer gelation is the reactant. Five to 10 second cures are indicative of latent or incipiently gelling reaction masses.

It has been found that such a product will remain stable, smooth and homogeneous, free of gel particles, and will not continue to polymerize or body appreciably after it has been cooled to room temperatures. The stability of super-high viscosity oils prepared by the above process is demonstrated by the absence of a tit or tail in the bubble when determining the viscosity in selected tubes or vials. As before mentioned, this tail formation has long been known as a, warning sign of instability and said indication when present gives notice thatgelation upon storage is likely.

The invention may be illustrated by the follow ing examples in which the quantities are stated in parts by weight.

Example I 8,000 parts varnish maker's linseed oil 40 parts anthraquinone 250 parts linseed fatty acid The linseed oil was heated in a varnish'kettle equipped with a blow ring along with a light carbon dioxide blow to 585 degrees F., adding the anthraquinone meanwhile. At 585 degrees F. a flow of sulfur dioxide gas was also bled into the hot oil. The exothermic reaction raised the oil temperature to 600 degrees F. at which point the temperature was maintained and the mixed gas blow continued for approximately 2 hours.

aeomsa.

Aqfter'. this 'period of'time'fthe viscosity oi the oil was between'25 to '85 minutes (i. e., incipient the tendency for "gel particles to'torm. The

batch was rapidly cooled below bodying' temperatures partly through adding-250 parts of,

linseed 'fatty acids.- The cooled oil had aviscosity of one hour and 'wasfree'of all semblance of gel particles.

f=This example illustrates :the bodying of "linseed oil, checking the batch with steam 'a-tEincipient, gelation and forming a super-polymerized oil having a viscosity in excess of "15 minutes yet free from gel particles.

' Emampleill 3 000 parts alkali refined soya bean oil 35 parts beta carboxyanthraquinone The oil and catalyst were heated to about 600 degrees meanwhile maintaining a light carbon dioxide blow through the bulk of the batch. Upon reaching the temperature of 590 degrees F. to 600 degrees F., the sulfur dioxide gas was turned on' and bled through the batch. After 5 hours at 600 degrees F., the oil was found to have attained a "cure point of seconds.

The batch was pulled ofi the fire and checked by adding water cautiously until the temperature Was-reduced to 480 degrees F.

Upon cooling asample of the oil to room temperature, it was found to have a final viscosity of 9minutes. I

This example illustrates the result obtained by checking with water as is sometimes done by the trade.

Example III Ihe batch made as in Example 11 was again pulled onto the fire, the temperature brought up .to1500 degrees F., the oil held for 15 to '20 minutes .at 500 degrees F. with a light steam blow. The batch was thereafter cooled by the addition of 350 pounds of rosin. i i fter rapid cooling of the batch an oil of 1-5 to '20 minutes viscosity was obtained, free of gel particles, and homogeneous in character.

Example LIV 7.0.00 parts varnish. makers linseed oil parts beta carboxyanthraquinone 350 parts rosin The varnish makers linseed .oil was heated to 400 degrees F.,"and the 35 parts of beta carboxyanthraquinone were; then added; meanwhile alight blow with an inert gas ;was maintained through the oil as it was further heated to 575 degrees F. Atthe latter temperature sulfur dioxide gas was also bled into the batch. The temperature increased to 590 degrees F. and was held at this temperature meanwhile maintaining the mixed gas blow for a little more than two hours. The oil at this time began to show evidences of more than one phase, or lack of homogeneity (e. g., incipient gelation), and the gases were shut-ofi and steam admitted through a blow ring in the kettle through the 'hot oil.

.The fire was cut and the batch held at 525 de grees F. for 15 to 20 minutes while the steam a '6 blow was continued. from'the fire, 350 parts of*rosin added to assist cooling and-check polymerization and the batch further cooled by water being directed on the outside area o f the kettle." Upon reaching-room temperature, an oil having avi'scosity in excess of one hour was obtaine The oil-was "homogeneous and free from gel particles. As iar as is known, stable oils of this viscosi-ty have not heretofore been produced atatmospheric pressures. 1

. e a T 1.1 7,-0.00- parts alkali refined 1 eeid oil. v290parts,reiinedtalloil 7 "The linseed oil was weighed into ausual van nish kettle equipped with gable-w i ing through which a light streamcf' arbo'ndioxide was passed, mainly to envelop th'e -posed' surface of the oil-to an inert atmosphere;

The batch was taken up to wd-degrees and maintained at this temperatu re plus or'minus 10 degrees F., for from '-8"zto"l0 hours, the-time being determined somewhat' by the --quality of "the oil and. the ability to jlcontrol the temperature at the point desired; T After-the oil had been held at the 'bodying temperature for this length g 3 and the batch rapidly cooled to below- 350 degrees F. by directing a stream crcold water on the outside areaio'fthe kettle.

The resulting "bodied o'il -'--was 'free from objectionable gel particles and' was smooth and homogeneous having a viscosity in' excess of one hour.

This example "illustrates the added time required'to body a -linseed oil to incipient gelation without aid of added'catalysts seeiExam'ple IV for comparison); and'theim'ethodo'f blowing with steam to disperse incipient 'gelation, 'and' further super-bodying of the oil yvith aifina'l check upon polymerization rate being'm'adewith a mixture of 'ros'in acids and fatty Loiltacids as they occur in tall 011, a by-product-trecovered Eirom the manufacture of paper.

'It is within the scope of the examples illustrative of my method that. resins may also be incorporated in :the oils .atsome time in the processing steps preferably after theoil. has been super-bodied. It may be zdesirable insome instances to include rosin esters or other resins in the .oil prior to the bodying operation, or it may be found 'more expedient ."to use additional amounts of resins .asichecking means after the oil has been suitably ibodied." v

Other means of Jrapid;; co oling after steam blowing of the oil while the temperature is maintained for the brief period :iol'lowingthe inc'ipient .gelation stage of: the :oil (are useful in lieu of :the addition of the specific agentshown in the foregoing examples. If the kettlesare heated by means of a liquid heat transfer'=medium (e. g., Dow-therm) cold .or cool tliqui'd heat transfer medium may be blendedwitnthe hoti medium in the jacket to force cool the completed batch in the kettle. .An -alternative;;method 10f cooling is to :continue to blow the batch j-Willh steam after shutting off the source oiQheat-tO the kettleof bodied oil, and continuing the .steam blow until the temperature has been "reduced sufficiently The jbatch was -r-emoved i-to;.;effectively retard polymerization. Another method which can be used (with due precaution due to dangerous ;consequence should negligence occur) is to spray a fine mist of water upon the surface of the hot oil thus extracting the sensible heat from the kettle until'the temperature has been sufficiently reduced to arrest reaction.

Theterm "quinone is employed in accordance with the usage in my previously described co-pending application to cover an organic, aromatic, unsaturated 1,3 in respect to both car-.

bon and oxygen, cyclic di-ketone containing at least six carbon atoms. The quinone compounds may be partially substituted, although the nonsubstituted quinones are preferred. Certain of these may be derived through oxidation of multiple ring compounds, e. g., phenanthrene.

Some quinoneswill sublime out of the unsaturated fatty acid polyesters at temperatures used for bodying oils, and it' is ;w ell ;know n that a blowing operation will hasten the removal of of starting materials for the purpose of the present invention, especially wherethe starting materials are derived from non-conjugated drying oils having an iodine'value greater'than 120.

The invention is hereby claimed as follows:

1. A process for the manufacture of superbodied fatty oils free; from gel particles and above 14 minutes in viscosity, which comprises heat-bodying an unsaturated fatty acid; polyester oil to ineipient'gelation within a 500 degrees F. to 625 degrees F. temperature range, blowing the said polyester with steam .while maintaining said temperatures until the viscosity is again more than 14 minutes,- and thereafter cooling the hot mass to inhibit further bodying action. I l

2. A process for the manufacture of homoeneous, gel particle-free fatty oils more viscous than heretoforeproducible at atmospheric pressures and above, which'coinprises heat-bodying an unsaturated fatty o'il acid polyester to incipient gelation within a 500 degrees F. to 625 degrees F. temperature range, dispersing the incipient gel by blowing with steam while maintaining said bodyin'gtemperatures until the viscosity level surpasses'that'attained prior to the start of the steam blow, and thereafter rapidly cooling the oil to below bodying temperature to inhibit further bodying action.

3. A method of manufacturing viscous homogeneous fatty oils free of gel particles, not heretofore producible at atmospheric pressures or above, which comprises heat-bodying an unsaturated fatty acid polyester oil to latent gelation within'a 500 degres'F. to 625 degrees F. temperature range at pressures "which are at least atmospheric, dispersing the latent gel with steam while maintaining oil bodying temperatures and thereafter rapidly cooling thebodied oil'to below bodying temperature. f

4. A method of manufacturing viscous homogeneous gel particle-free fatty oils more viscous than heretofore producible atatmospheric pressures and above, which comprises catalytically heat-bodying an unsaturated fatty acid polyester oil to latent gelation within a 500 degrees F. to 625 degrees F. temperature range at pressures which are at least atmospheric, dispersing the latent gel by blowing with steam while maintaining bodying temperatures until .the viscosity surpasses that attained prior to the steamblow, and thereafter cooling the oil and checking the polymerization rate.

5. A method of manufacture of an oilcharacterized by a higher viscositythan heretofore produced at atmospheric pressures {and above, homogeneous and free from gel particles, which comprises heat-bodying an unsaturatedv fatty acid polyester oil in the presence of a quinone and sulfur dioxide until the viscosity becomes indeterminant, checking the latently gelling oil by blowing with steam until a viscosity at least above 14 minutes has been regained while maintaining a temperature of from 500 degrees F. to 625 degrees F., and thereafter cooling the said super-bodied fatty acid polyester oil to below bodying temperatures.

6. A method of manufacture of an oil characterized by a higher viscosity than heretofore produced at atmospheric pressures and above, homogeneous and free from gelparticles, which comprises heat-bodying an unsaturated soya bean acid polyester oil in the presence of a quinone and sulfur dioxide until the viscosity becomes indeterminant, checking the latently gelling oil by blowing with steam until a viscosity at least above 14 minutes has been regained while maintaining a temperature of from.500 degrees F. to 625 degrees F., and thereafter cooling the said super-bodied soya bean acid polyester oil to beloW bodying temperatures.

'7. A method of manufacture of an oil characterized by a higher viscosity than heretofore produced at atmospheric pressures and above, homogeneous and free from gel particles, which comprises heat-bodying an unsaturated linseed acid polyester oil in the presence of a quinone and sulfur dioxide until the. viscosity becomes indeterminant, checking the latently gelling oil by blowing with steam until a viscosity at least above 14 minutes has been regained while maintaining a'temperature of from 500 degrees F. to 625 degrees F., and thereafter cooling the said super-bodied linseed acid polyester oil to below bodying temperatures.

8. A method of manufacturing viscous fatty oils, free of gel particles, which comprises heatbodying an unsaturated fatty acid polyester oil until latent gel particles become incipient within a 500 degrees F. to 625 degrees F. temperature range, steam blowing the saidoil by spraying with water and maintaining saidtemperature until theviscosity surpasses that developed prior to the steam blow, and adding rosin thereafter to cool and inhibit further 'bodying actions JAMES A. ARVIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. A PROCESS FOR THE MANUFACTURE OF SUPERBODIED FATTY OILS FREE FROM GEL PARTICLES AND ABOVE 14 MINUTES IN VISCOSITY, WHICH COMRPRISES HEAT-BODYING AN UNSATURATED FATTY ACID POLYESTER OIL TO INCIPIENT GELATION WITHIN A 500 DEGREES F. TO 625 DEGREES F. TEMPERATURE RANGE, BLOWING THE SAID POLYESTER WITH STEAM WHILE MAINTAINING SAID TEMPERATURES UNTIL THE VISCOSITY IS AGAIN MORE THAN 14 MINUTES, AND THEREAFTER COOLING THE HOT MASS TO INHIBIT FURTHER BODYING ACTION 